The present invention relates to a control cable length self-adjusting mechanism which, specifically, is applicable to the adjustment of the length of sheathed steel cables which are regularly used in control and regulation devices and, in particular, to the automobile industry.
Sheathed steel control cables are widely used in the automobile industry as a means linking devices such as, for example, the clutch pedal and the plate operating lever, or in automatic gear change controls, connecting the gear change lever to the gearbox. The control cables are usually designed for mounting with a small number of operations in the motor vehicle. Such control cables, which are dimensioned and provided at the ends thereof with corresponding connection terminals adapted to each particular application, incorporate a control cable length self-adjusting device for compensating the variations which arise during the assembly process in each particular vehicle with regard to the theoretical distance between the mechanisms connected by said cable.
The self-adjusting device performs the function of automatically regulating and setting the optimum length of the control cable during the assembly of the latter in the vehicle, once attached by way of the connection terminals disposed at the respective ends to the mechanisms it connects, with the said self-adjusting device being anchored to a fixed point of the motor vehicle structure.
The known embodiments of control cable length self-adjusting devices comprise all or some of the following operative members:
a main body member through which an adjusting stud may suitably slide. This is provided with a retaining screw thread and is firmly attached at one end thereof to the sheath of the steel cable. The steel cable, unsheathed, may slide longitudinally through the adjusting stud. The main body member is provided with mechanical means allowing it to be anchored to a fixed point of the motor vehicle structure. PA1 retaining means disposed inside the main body member. These means operate on the adjusting stud so as to set the position thereof relative to the said fixed point. PA1 and a control spring coaxially disposed relative to the adjusting stud. This spring presses permanently against the main body member and against the adjusting stud at the end thereof attached to the steel cable sheath.
The above described control cable length self-adjusting devices are supplied with the control spring compressed. Under these conditions, the devices operate as follows: when the control cable is attached by the terminals at both ends to the mechanisms it connects and the main body member is anchored to a fixed point on the vehicle structure, the adjusting stud is released from the retaining means and under the urging of the control spring it establishes the appropriate length of the sheathed steel cable between the adjusting stud and the corresponding mechanism. Thereafter the new position of the adjusting stud relative to the fixed point is set with the retaining means, with the control cable length being appropriately set in this way for the appropriate functioning of the mechanisms connected thereby.
As an embodiment of said control cable length self-adjusting devices, there may be cited Spanish patent P 8803905 for "Control cable tension self-adjusting device" which, comprises all the operative members described above.
Generally speaking, the known embodiments of control cable length self-adjusting devices have all or some of the following drawbacks limiting their operativity:
(a) they require tools for manipulating the retaining means mounted in the main body member which operate on the adjusting stud during the operations of adjusting and setting the control cable length; and
(b) the manipulating on the retaining means during the operations of adjusting and setting the control cable length is transversal to the axis defined by the adjusting stud.
Such limitations cause an increase of the cost of installation of the control cables in all those cases in which the self-adjusting device is located, for needs derived from the design and/or location of the devices connected by the control cable, in points of the motor vehicle structure of difficult and/or limited access which greatly hinder the use of tools under appropriate conditions and/or there is not sufficient space to work transversely on the retaining means operating on the adjusting stud.